Closed-loop extraction is not new or unique to the cannabis industry. For many years people have used closed-loop extraction to extract essential oils for things like food additives and perfumes. Recently, however, it has become a widely popular cannabis extraction method. Cannabis industry professionals use closed-loop extraction to extract cannabinoids (THC, CBD) and terpenes from cannabis plant material into an isolated concentrate.

Closed-loop extraction is a form of hydrocarbon extraction. However, unlike other variations of hydrocarbon extraction, closed-loop extraction occurs entirely within a closed system, which keeps the solvent from making any contact with the outside atmosphere. Closed-loop extraction offers benefits that other extraction methods are unable to provide, such as safety and efficiency.

What is Closed-Loop Extraction?

Closed-loop extraction uses solvents to extract cannabinoids. In the closed-loop system, solvent moves from a containment tank into an area where it can wash over the cannabis plant material. The closed-loop system recycles the solvent, so it washes over the cannabis many times repeatedly. This washing dissolves the cannabinoids and terpenes from the cannabis plant material. The concentrate is then refined, purged of the solvent, and collected.

The most common solvents to use in closed-loop extraction include the hydrocarbons butane, propane, and ethanol. Industry professionals also use carbon dioxide during extraction.

01. High pressure food grade hoses: the tube used to transfer liquid phase butane
02. Solvent tank: the container used to contain solvents
03. Product tubes: the tube used to transfer production
04. Collection chamber: the container used to collect oil
05. Recovery pump:used to provide pressure to recover the solvents
06. Material column: the reactor that cannabis gets extracted

The key closed-loop extraction benefits include safety, efficiency, cost-effectiveness, and higher quality products.

Safety

One key closed-loop extraction benefit is safety.  Cannabis industry professionals regard closed-loop extraction as the safest way to extract cannabinoids.

Hydrocarbon solvents are flammable, pressurized gases. In closed-loop extraction systems, there are no opportunities for leaks if the equipment is maintained and operated at the appropriate standards. A contained system makes the risk of hazard almost non-existent. In fact, in our several thousand installations, we have never had a client have a safety issue or accident with Precision equipment.

Efficiency

Another closed-loop extraction benefit includes a higher-pressure capacity than open-loop extraction equipment. High pressure allows for maximum extraction of cannabinoids.

In addition to controlling temperature, closed-loop extraction systems are excellent at regulating temperature. Temperature directly controls the solubility of cannabinoids, so it’s essential to be able to control the temperature in the system.

Closed-loop extraction systems also prevent the solvent from being evaporated into the atmosphere and allow the solvent to be used many times without needing to be recharged.

Cost-effectiveness

One huge closed-loop extraction benefit is that hydrocarbon solvent is unable to leak out into the atmosphere. Equipment operators can reuse the solvent for extraction after extraction. This benefit leads to savings on solvent purchasing costs for businesses.

Higher-quality product

Closed-loop extraction technologies provide exceptional control over pressure and temperature, which offer an opportunity to produce the strongest, purest cannabis concentrates available. The vacuum oven removes most or all of the solvent’s residue, so many consumers also regard closed-loop extraction products as the safest to consume.

Closed-loop systems vary mechanically, depending on the solvent that will be used. However, the general method remains the same. There are three main containment areas: a vessel that contains the primary solvent, one for the cannabis plant material, and one that is used to collect the resulting extract.

Depending on the type of solvent being used, e.g. butane or carbon dioxide (CO2), the solvent may need to pass through the cannabis plant matter multiple times in order to strip off all the precious compounds, such as the cannabinoids and terpenes. For instance, butane is one of the most effective solvents and is capable of extracting almost all of the essential properties in one loop through the system. On the other hand, CO2 is a much more selective solvent and will take several more runs, and several more hours, to fully capture all the intoxicating and therapeutic properties of the cannabis plant.

The process begins with a tank of liquid solvent or a gas that is mechanically converted into a liquid solvent. The next step is to allow the liquid solvent to flow into the tank with the cannabis buds or trim. At this point, the solvent will dissolve the active compounds in the plant and create a solution. The final tank is where the resulting extract goes and where the initial solvent used is evaporated from the solution through the use of heat. When the solvent evaporates into a gas, it rises and is condensed back into the first tank. The solvent can then be reused, either on the same cannabis or for a fresh batch.